U.S. patent application number 12/064539 was filed with the patent office on 2012-03-01 for secondary contained csst pipe and fitting assembly.
Invention is credited to Thomas B. Lininger, Nicholas Novak, Steven M. Powell.
Application Number | 20120049509 12/064539 |
Document ID | / |
Family ID | 37488059 |
Filed Date | 2012-03-01 |
United States Patent
Application |
20120049509 |
Kind Code |
A1 |
Lininger; Thomas B. ; et
al. |
March 1, 2012 |
SECONDARY CONTAINED CSST PIPE AND FITTING ASSEMBLY
Abstract
A double wall pipe assembly includes an inner primary pipe (4)
and an outer secondary pipe (5), as well as a novel fitting
assembly (3) for terminating the double wall pipe assembly. The
primary pipe is a flexible annularly corrugated pipe made from
stainless steel which is flexible and nearly impermeable to fuels.
The fitting assembly provides an integrated seal of the secondary
pipe to a fastener (8) used to seal the primary pipe to fitting
body. The fitting assembly may also maintain communication between
an interstitial space between the primary and secondary pipes and
an access port (182) in the fastener. The access port can be used
for monitoring of the interstitial space between the primary and
secondary pipe.
Inventors: |
Lininger; Thomas B.;
(Mantua, OH) ; Powell; Steven M.; (Chardon,
OH) ; Novak; Nicholas; (Willowick, OH) |
Family ID: |
37488059 |
Appl. No.: |
12/064539 |
Filed: |
August 22, 2006 |
PCT Filed: |
August 22, 2006 |
PCT NO: |
PCT/US06/32627 |
371 Date: |
February 5, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60710261 |
Aug 22, 2005 |
|
|
|
Current U.S.
Class: |
285/93 ; 138/114;
285/123.1 |
Current CPC
Class: |
F16L 2101/30 20130101;
F16L 9/06 20130101; F16L 9/18 20130101; F16L 2201/30 20130101; F16L
39/005 20130101; F16L 39/02 20130101; F16L 25/0036 20130101 |
Class at
Publication: |
285/93 ;
285/123.1; 138/114 |
International
Class: |
F16L 39/00 20060101
F16L039/00; F16L 25/00 20060101 F16L025/00; F16L 9/18 20060101
F16L009/18; F16L 9/06 20060101 F16L009/06 |
Claims
1. A flexible double wall pipe assembly comprising an inner primary
pipe for conveying a fluid and an outer secondary pipe surrounding
the primary pipe for containing any fluid leaks from the primary
pipe, wherein the inner primary pipe and outer secondary pipe
define therebetween an interstitial space extending along the
lengths thereof to allow any fluid released from the primary pipe
to flow along the length of the interstitial space, and the inner
primary pipe is a flexible annularly corrugated pipe having annular
valley portions alternating with annular crest portions that define
a major outer diameter of the pipe.
2. A double wall pipe assembly according to claim 1, wherein the
corrugated pipe is made of stainless steel.
3. A double wall pipe assembly according to claim 1, wherein the
secondary pipe is made of a thermoplastic material.
4. A double wall pipe assembly according to claim 1, wherein
radially outwardly disposed annular crests of the corrugated pipe
have one or more axially extending recesses formed therein for
providing increased flow area between the primary and secondary
pipes at the regions of the radially outwardly disposed annular
crests.
5. A double wall pipe assembly according to claim 4, wherein the
radially outwardly disposed annular crests each have a plurality of
the recesses formed therein and the recesses are annularly spaced
apart.
6. A double wall pipe assembly according to claim 1, in combination
with a fitting assembly, the fitting assembly comprising a fitting
body having a threaded end portion, a fastener having a threaded
portion for threadedly engaging the threaded portion of the fitting
body, and a collet which is receivable coaxially within the
fastener, wherein the fitting body has a socket for receiving the
collet and an annular sealing surface at an inner end of the
socket, the collet includes a circumferential arrangement of
axially extending segments having sufficient radial flexibility to
allow the annular crests of the corrugated pipe to pass axially
through the collet for engagement of an end of the corrugated pipe
against the sealing surface of the fitting body, and the fastener
is engageable with the collet when tightened on the fitting body to
urge the collet axially for causing distal ends of the segments to
urge a corrugation at the end of the corrugated pipe into sealing
engagement with the sealing surface of the fitting body.
7. A pipe and fitting combination according to claim 6, wherein the
fastener includes a tubular portion opposite its threaded portion,
the tubular portion being configured to receive an end portion of
the outer secondary pipe, and there is provided a coupling device
for securing the end portion of the outer secondary pipe in fluid
tight relationship to the tubular portion of the fastener.
8. A pipe and fitting combination according to claim 7, wherein the
coupling device includes one or more of a compression fitting,
bonded joint, a push-to-connect mechanism, or a clamp.
9. A pipe and fitting combination according to claim 6, wherein the
fastener includes an interior space in fluid communication with the
interstitial space between the primary and secondary pipes, and an
access port extending from the interior space to the exterior of
the fastener.
10. A pipe and fitting combination according to claim 9, wherein
the access port is a view port allowing visual viewing of the
interior space from outside the fastener.
11. A pipe and fitting combination according to claim 9, wherein
the port is threaded.
12. A pipe and fitting combination according to claim 9, wherein
the interior space is at least partly defined by the fastener and
the fitting body, and a seal is interposed between the fastener and
the fitting body to seal the interior space with respect to the
outside.
13. A fitting assembly for a flexible double wall pipe assembly
that includes an inner primary pipe for conveying a fluid and an
outer secondary pipe surrounding the primary pipe with an
interstitial space formed between the pipes and extending along the
lengths thereof, the fitting assembly comprising a fitting body
having a threaded end portion, and a fastener having a threaded
portion for threadedly engaging the threaded portion of the fitting
body and for securing the primary pipe to the fitting body, and
wherein the fastener includes a tubular portion opposite its
threaded portion, the tubular portion is configured to receive an
end portion of the outer secondary pipe, and there is provided a
coupling device for securing the end portion of the outer secondary
pipe in fluid tight relationship to the tubular portion of the
fastener.
14. A fitting assembly according to claim 13, wherein the coupling
device includes one or more of a compression fitting, bonded joint,
a push-to-connect mechanism, or a clamp.
15. A fitting assembly according to claim 13, wherein the fastener
includes an interior space for fluid communication with the
interstitial space between the primary and secondary pipes, and an
access port extending from the interior space to the exterior of
the fastener.
16. A fitting assembly according to claim 15, wherein the access
port is a view port allowing visual viewing of the interior space
from outside the fastener.
17. A fitting assembly according to claim 15, wherein the access
port is threaded.
18. A fitting assembly according to claim 15, wherein the interior
space is at least partly defined by the fastener and the fitting
body, and a seal is interposed between the fastener and the fitting
body to seal the interior space with respect to the outside.
19. A fitting assembly for a flexible double wall pipe assembly
that includes an inner primary pipe for conveying a fluid and an
outer secondary pipe surrounding the primary pipe with an
interstitial space formed between the pipes and extending along the
lengths thereof, the fitting assembly comprising a fitting body,
and a fastener for connecting the primary and secondary pipes to
the fitting, wherein the fastener includes an access port for
connecting to the interstitial space when the primary and secondary
pipes are connected to the fitting body by the fastener.
Description
RELATED APPLICATIONS
[0001] The present application claims the benefit of the filing
date of U.S. Provisional Application No. 60/710,261, filed Aug. 22,
2005, the disclosure of which is incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The invention herein described relates generally to
secondarily contained pipes and fittings and more particularly to
secondarily contained annularly corrugated steel tube pipes and
fittings useful, in particular, for the underground transport of
hydrocarbon fuels and solvents.
BACKGROUND OF THE INVENTION
[0003] Secondary containment pipes (also termed "coaxial") are
typically used in fuel station installations where a primary pipe
is the main supply between an underground storage tank and the pump
and the secondary pipe surrounds the primary pipe along the length
thereof and is terminated at a sump or a fluid detection sensor.
Secondary containment pipes are used to contain unintentional fluid
release from the primary pipe. Typically an "interstitial space" is
provided between the primary and secondary pipes to allow any
released fuel to flow to a containment sump or to a sensor.
[0004] All thermoplastic containment pipes for fuel delivery
applications have been used for many years by companies like OPW
Fueling Components (U.S. Pat. No. 5,098,221) and Environ Products
(U.S. Pat. Nos. 5,263,794 and 5,297,896). In some pipe assemblies,
internal ribs have been employed to space the containment pipe from
the primary pipe, such as is shown in U.S. Pat. No. 5,611,373.
Brugg Rohrsysteme in Germany makes a primary and secondary fuel
pipe assembly with a flexible, helically corrugated stainless steel
(CSST) primary pipe and an outer thermoplastic containment pipe
that is separated from the primary pipe by various means (European
Patent Publication Nos. 0890768A2, 0890768B1, 0890769A2, and
1219882A2). The Brugg Rohrsysteme uses bitumen (graphite) to effect
a seal between the primary pipe and the associated fitting.
[0005] Annularly corrugated, as well as spirally corrugated, metal
tubing, often fabricated of stainless steel or copper and jacketed
with a plastic material, is commonly employed in residential or
commercial building constructions as a transitional fluid conduit
extending between an appliance or other machine and a rigid
auxiliary line, pipe, or other connection of a fuel source which
may be natural gas, propane, or the like. The flexibility of such
tubing facilitates the alignment of couplings and other
connections, and also accommodates limited movement of the
appliance or machine with respect to the rigid connection of the
fuel source.
[0006] Recently, tubing of such type, and particularly corrugated
stainless steel tubing, has been employed as a substitute for
traditional hard, i.e., inflexible, steel or iron "black" pipe in
gas line applications for residential and commercial construction.
Advantageously, the flexibility of the tubing facilitates its
installation through walls, ceilings, and floors and, especially,
the alignment of the tubing connections. Moreover, such tubing is
lightweight, easy to carry, requires no threading or heavy
equipment therefor, allows the use of fewer fitting connections,
and exhibits less leak potential than conventional, hard piping.
Corrugated tubing additionally is used in other fluid transport
applications such as in air conditioning, hydraulics, and general
plumbing, and also as conduit for electrical applications. Tubing
manufacturers include the Parflex Division of Parker-Hannifin
Corp., Ravenna, Ohio, Titeflex Corp. of Springfield, Mass.,
OmegaFlex, Inc. of Exton, Pa., and Wardflex Manufacturing of
Blossburg, Pa.
[0007] Compression and other fitting connections are commonly used
in natural gas line and other applications. As shown, for example,
in commonly-assigned U.S. Pat. Nos. 6,036,237; 6,019,399;
6,428,052; 6,173,995; 6,079,749; 5,799,989; 5,441,312; 5,292,156;
5,226,682; 5,080,405; 4,904,002; 4,630,850; 4,674,775; 2,549,741;
and 2,323,912, and in U.K. Patent No. 1,371,609, such connections
typically involve a nut and an associated collet, split ring,
ferrule, flare, C-ring or rings, bushing, sleeve, or other
compression or locking member which is received in or over the tube
end for holding the tube end within the nut as the nut is tightened
onto a nipple, adapter, body or other connector.
[0008] As the use of corrugated tubing in gas line and other fluid
transfer applications continues to increase, it will be appreciated
that further improvements in the design of fitting connections
therefor would be well-received. A preferred design would be
economical to manufacture, but would also simplify the assembly of
the coupling while providing a connection which minimizes the
potential for leaks and the like. Also, applicants have appreciated
it would be advantageous to extend the use of annularly corrugated
tubes to secondarily contained pipe assemblies and particularly
such assemblies suitable for underground transport of hydrocarbon
fuels and solvents.
SUMMARY OF THE INVENTION
[0009] The present invention provides a novel double wall pipe
assembly including an inner primary pipe and an outer secondary
pipe, as well as a novel fitting assembly for terminating the
double wall pipe assembly. The primary pipe preferably is a
flexible annularly corrugated pipe made from stainless steel which
is flexible and nearly impermeable to fuels. The secondary pipe can
be multilayer with yarn reinforcement for higher pressure capacity
or improved flexibility. The secondary containment pipe can be
annularly or helically corrugated for improved flexibility.
[0010] The fitting assembly provides a unique integrated seal of
the secondary pipe to a fastener used to seal the primary pipe to
fitting body. The fitting assembly may also maintain communication
between an interstitial space between the primary and secondary
pipes and an access port in the fastener. The access port can be
used for monitoring of the interstitial space between the primary
and secondary pipe. Also, a preferred fitting assembly enables
quick "push-In and tighten" attachment of the pipe assembly to
facilitate onsite assembly, as well as a reliable metal-to-metal
seal of the primary pipe to a mating fitting body.
[0011] Accordingly, a flexible double wall pipe assembly comprises
an inner primary pipe for conveying a fluid and an outer secondary
pipe surrounding the primary pipe for containing any fluid leaks
from the primary pipe. The inner primary pipe and outer secondary
pipe define therebetween an interstitial space extending along the
lengths thereof to allow any fluid released from the primary pipe
to flow along the length of the interstitial space, and the inner
primary pipe is a flexible annularly corrugated pipe having annular
valley portions alternating with annular crest portions that define
a major outer diameter of the pipe.
[0012] The corrugated pipe preferably is made of stainless steel,
and the secondary pipe may be made of metal or a thermoplastic
material, and further may be annularly or helically corrugated. The
radially outwardly disposed annular crests of the corrugated pipe
may have one or more axially extending recesses formed therein for
providing increased flow area between the primary and secondary
pipes at the regions of the radially outwardly disposed annular
crests.
[0013] According to another aspect of the invention, the fitting
assembly comprises a fitting body having a threaded end portion,
and a fastener having a threaded portion for threadedly engaging
the threaded portion of the fitting body and for securing the
primary pipe to the fitting body. The fastener includes a tubular
portion opposite its threaded portion, and the tubular portion is
configured to receive an end portion of the outer secondary pipe. A
coupling device is provided for securing the end portion of the
outer secondary pipe in fluid tight relationship to the tubular
portion of the fastener.
[0014] The coupling device may include one or more of a compression
fitting, bonded joint, a push-to-connect mechanism, or a clamp.
[0015] In a preferred embodiment, the fastener includes an interior
space for fluid communication with the interstitial space between
the primary and secondary pipes, and an access port extending from
the interior space to the exterior of the fastener. The access port
may be a view port allowing visual viewing of the interior space
from outside the fastener, or the access port may be configured for
connection to a conduit for remote sensing or other purposes. The
interior space may be at least partly defined by the fastener and
the fitting body, and a seal may be interposed between the fastener
and the fitting body to seal the interior space with respect to the
outside.
[0016] Further features of the invention will become apparent from
the following detailed description when considered in conjunction
with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] An exemplary embodiment of the invention is illustrated in
the accompanying drawings in which:
[0018] FIG. 1 is a cutaway, perspective view of an exemplary
flexible double wall pipe assembly and associated fitting assembly
in accordance with the present invention, with an inner primary
corrugated pipe of the pipe assembly shown only partially inserted
into a fitting assembly;
[0019] FIG. 2 is a part cross-sectional, part elevational view of
the assemblies of FIG. 1;
[0020] FIG. 3 is view similar to FIG. 2, but showing the primary
corrugated pipe substantially fully inserted into a fitting body
that forms part of the fitting assembly;
[0021] FIG. 4 is an enlarged portion of FIG. 3;
[0022] FIG. 5 is a perspective view of a collet employed in the
fitting assembly;
[0023] FIG. 6 is a part cross-sectional, part elevational view of
the collet, taken along line 4-4 of FIG. 5;
[0024] FIG. 7 is a fragmentary, part cross-sectional, part
elevational view showing the fitting assembly tightened to effect a
seal between the primary corrugated pipe and the fitting body;
and
[0025] FIG. 8 is a fragmentary cross-sectional view of the wall of
the corrugated primary pipe, showing a recess formed in a crest
thereof.
DETAILED DESCRIPTION
[0026] Certain terminology may be employed in the following
description for convenience rather than for any limiting purpose.
For example, the terms "forward" and "rearward," "front" and
"rear," "right" and "left, upper" and "lower," "top" and "bottom,"
and "right" and "left" designate directions in the drawings to
which reference is made, with the terms "inward," "inner,"
"interior," or "inboard" and "outward," "outer," "exterior," or
"outboard" referring, respectively, to directions toward and away
from the center of the referenced element, the terms "radial" or
"vertical" and "axial" or "horizontal" referring, respectively, to
directions, axes, or planes perpendicular and parallel to the
longitudinal central axis of the referenced element, and the terms
"downstream" and "upstream" referring, respectively, to directions
in and opposite that of fluid flow. Terminology of similar import
other than the words specifically mentioned above likewise is to be
considered as being used in a relational sense for purposes of
convenience.
[0027] In the figures, elements having an alphanumeric designation
may be referenced herein collectively or in the alternative, as
will be apparent from context, by the numeric portion of the
designation only. Further, the constituent parts of various
elements in the figures may be designated with separate reference
numerals which shall be understood to refer to that constituent
part of the element and not the element as a whole. General
references, along with references to spaces, surfaces, dimensions,
and extents, may be designated with arrows. Angles may be
designated as "included" as measured relative to surfaces or axes
of an element and as defining a space bounded internally within
such element therebetween, or otherwise without such designation as
being measured relative to surfaces or axes of an element and as
defining a space bounded externally by or outside of such element
therebetween. Generally, the measures of the angles stated are as
determined relative to a common axis, which axis may be transposed
in the figures for purposes of convenience in projecting the vertex
of an angle defined between the axis and a surface which otherwise
does not extend to the axis. The term "axis" may refer to a line or
to a transverse plane through such line as will be apparent from
context.
[0028] For the illustrative purposes of the discourse to follow,
the precepts of the fitting connection for the flexible double wall
pipe assembly involved are described in conjunction with a
"straight" fitting and assembly therefor particularly adapted for
underground transport of hydrocarbon fuels and solvents. It is to
be appreciated, however, that the present invention may find
utility in other connector configurations, such as adapters,
unions, tees, elbows, and crosses, and as integrated or other port
connections for valves, cylinders, manifolds, sensors, and other
fluid components, as well as in other applications for flexible
secondarily contained pipes. Use within these and other
configurations and applications therefore should be considered to
be expressly within the scope of the invention herein involved.
[0029] Referring now to the figures wherein corresponding reference
characters are used to designate corresponding elements throughout
the several views with equivalent elements being referenced with
prime or sequential alphanumeric designations, an exemplary
flexible double wall pipe assembly and associated fitting assembly
according to the present invention are respectively designated by
reference numerals 2 and 3 in FIG. 1. The flexible double wall pipe
assembly includes a flexible inner primary pipe 4 for conveying a
fluid and a flexible outer secondary pipe 5 surrounding the primary
pipe (the term "pipe" is intended to encompass tube, tubing and the
like). The secondary pipe 5 serves as a containment pipe for
capturing any fluid leaks from the primary pipe within an
interstitial space 6 formed between the pipes and extending along
the lengths thereof to allow any fluid released from the primary
pipe to flow along the length of the interstitial space. The
fitting assembly 3 comprises a fitting body 7 having an exteriorly
threaded end, and a fastener 8, such as a nut. The fastener 8 has
an internally threaded portion for threadedly engaging the threaded
portion of the fitting body and for securing the primary pipe to
the fitting body. The fastener 8 further includes a tubular portion
9 opposite its internally threaded portion. The tubular portion 9
is configured to receive an end portion of the outer containment
pipe, such end portion being secured in fluid type relationship to
the fastener by a coupling device 10.
[0030] The primary pipe 4 preferably is a flexible annularly
corrugated pipe that preferably is made of metal and particularly
stainless steel. The preferred primary pipe has annular valley
portions alternating with annular crest portions that define a
major outer diameter of the pipe.
[0031] The secondary (or containment) pipe 5 may also be a flexible
annularly corrugated pipe that may be made of metal such as
stainless steel. Spirally corrugated pipe may be used, and the
corrugated pipe may be formed from other materials such as a
thermoplastic. In still further embodiments, non-corrugated
flexible pipe may be used. Thermoplastic pipe may be made of a fuel
resistant thermoplastic(s) such as polyamide,
polytetrafluoroethylene, fluorinated-ethylene propylene,
perfluoroalkoxy, polyvinyl alcohol, ethylene vinyl alcohol
polyethylene, polyphenelyne sulfide, polyacetal copolymer,
polyvinylidene fluoride, ethylene-tetrafluoroethylene,
ethylene-fluorinated ethylene propylene or
ethylene-chlorotrifluoro-ethylene. The pipe may be a bi-layer
consisting of an inner liner material of a fuel resistant
thermoplastic such as listed above with a lower cost, lower
compatibility material used to form an outer layer of the pipe. The
pipe alternatively may have a fuel resistant thermoplastic inner
liner with a layer of aluminum strip, which is resistant to fuels,
and an outer layer of thermoplastic, which may or may not be fuel
resistant.
[0032] Primary Pipe-Fitting Connection
[0033] The fitting assembly 3 preferably is configured to terminate
the primary pipe 4 in a manner similar to that described in U.S.
Pat. No. 6,908,114, which is hereby incorporated herein by
reference. Accordingly, the fitting assembly 3 further comprises a
generally annular collet 20 which is receivable coaxially within
the fastener 8 and the fitting body 7.
[0034] The illustrated exemplary fitting body 7 has a straight
configuration, but could be of other configurations such as an
elbow, tees, crosses, etc. The fitting body is generally tubular
with an internal axial throughbore 24 extending coaxially with a
central longitudinal axis 26. By way of convention, axial
directions along axis 26, which for purposes of convenience will be
used as a common reference axis for each of the components of the
illustrated fitting assembly 3, will be referred to as "forward,"
"forwardly," or "front" if in the direction of or towards or
adjacent a body forward end portion 28, and as "rearward,"
"rearwardly," or "rear" if in the opposite direction of or towards
or adjacent the body rearward end portion 30.
[0035] The forward end portion 28 of the fitting body 7 may be
suitably configured for connection to a further component, although
it will be appreciated that the fitting body may itself be formed
integrally in another component. For example, the end portion 28
may be threaded for a male threaded pipe connection, and the outer
surface of the fitting body may be provided wrenching surfaces such
as flats 32 arranged in a hexagonal pattern for engagement by a
wrench or other tool during make-up or disassembly of the fitting
connection. The forward end portion 28 alternatively may be
configured instead for a female threaded pipe connection, or for a
tube, welded or other connection.
[0036] The rearward end portion 30 of the fitting body 7 is
externally threaded as shown at 34 in FIG. 4.
[0037] As further shown in FIG. 4, the fitting body bore 24 is
counterbored beginning from the opening of the body rearward end
and ending intermediate the rearward end and the opening of the
forward end of the fitting so as to define a larger diameter
rearward end portion or socket 40 having a rearwardly-facing,
lead-in chamfer 41 and an inner circumferential surface 42 which
may transition to a rearward taper 43 and a smaller diameter
forward end portion 44 having an inner circumferential surface 46
which, as is shown, may be generally cylindrical. The rearward end
portion 40 terminates at a generally upstanding, annular end wall
48 which adjoins the taper 43 and which, in turn, extends radially
inwardly in transitioning to a rearwardly-facing, tapered sealing
or seating surface 50 which may have a generally annular,
frustoconical geometry in being inclined or angled in the forward
axial direction along axis 26. The sealing surface 50 itself may
transition by way of a rounded or radiused apex 51 to a chamfer 52,
so as to define an inside angle .alpha., which may be acute, but
which alternatively may be obtuse. Other configurations of the
sealing surface may also be used if desired.
[0038] The opening at the body rearward end 30 is sized to accept
the distal end 12 of the primary pipe 4 for insertion into the
fitting body 7. The primary pipe 4 is conventionally formed of a
series of sinusoidal corrugations, a first one of which is
referenced at 60. These corrugations define valleys or valley
portions 64 alternating with crests or crest portions 62. The
valleys define a minor outer diameter of the primary pipe and the
crests define the outer periphery, i.e., major outer diameter, of
the primary pipe. As is shown at 66, distal end 12 of pipe 4 is
formed by cutting through, preferably centrally, of the first one
of the valleys 64, which also herein referred to as a root or
trough portions.
[0039] Referring now to FIGS. 5 and 6, the collet 20 in the
illustrated embodiment is formed as a composite of a forward
portion, referenced at 70, and a rearward portion, referenced at
72. The collet forward portion 70 is constructed of a number of
individual, arcuate tangs, one of which is referenced at 74,
arranged in a series circumferentially about axis 26, with the
collet rearward portion 72 being constructed as a generally
annular, flexible retaining collar 76, which resiliently retains
the individual tangs 74 of the forward portion 70 in their
circumferential arrangement about axis 26.
[0040] As arranged in such series, each of the tangs 74 may be
generally abutting or adjoining, i.e., the sides thereof are not
separated by substantial spaces therebetween, and define a major
inner diametric extent of the collet forward portion 70 which may
be incrementally larger than the major outer diameter of the
primary pipe 4 (FIGS. 1-3), so as to allow the primary pipe distal
end 12 to be received coaxially therethrough. In the illustrated
embodiment, each of the eight tangs 74 which are shown is of an
about equal radial extent which usually would be preferred. The
number of tang segments comprising the collet forward portion 70
may vary as generally depending upon the nominal diameter of collet
20, but typically will be at least two and may be eight as shown,
or more, or any number therebetween.
[0041] Each of the arcuate tangs 74 forming the collet forward
portion 70 may extend from a rearward end 80, which may be
configured, as shown, as a generally upstanding flange, having a
slot 82 therethrough, to a forward end 84. The slot 82 may have a
generally L-shaped axial cross-section in extending from the
backside 86 of the rearward end 80, through to the topside 88 of
the end 80. The slot 82 may extend through the topside 88 and may
have a generally wedged-shaped radial cross-section.
[0042] At the forward end 84, tang 74 may be configured as having
rearwardly-facing angled surface 90 and an adjoining
forwardly-facing angled surface 92. At truncated, flattened,
radiused, or other vertex thereof the surfaces 90 and 92 define a
radially inwardly-extending, generally conical tooth or other
gripping or retaining portion 94, receivable within a pipe root
portion 64 (FIG. 4). In the circumferential arrangement of the
tangs 74 about the axis 26, the surfaces 92, which may be generally
parallel to the body sealing surface 50 in the assembled
connection, may form in the normal, unexpanded or closed
orientation of the collet 20, a circular, generally conical or
frustoconical, annular ring about the axis 26. The ring 95 defines
a minor inner diametric extent of the collet forward portion 70
which may approximate or be incrementally larger than the primary
pipe minor outer diameter, but otherwise smaller than the primary
pipe major outer diameter, such that, when received within one of
the pipe root portion 64, the tang retaining portions 94 hold the
primary pipe 4 and thereby delimit the axial movement thereof
relative to the collet 20. Advantageously, the shape of such ring,
which may be generally non-collapsing due to the abutment between
the side of each of the tangs with the corresponding side of each
adjacent tang, need not deviate substantially from circularity, and
in that regard may function as a solid ring to help more reliably
seal the pipe end against the body sealing surface.
[0043] The forward end 84 of each of the tangs 74 further may be
configured as having an outer chamfered surface 96, which may form
a leading edge of the collet 20. Each of the collet tangs 74 have
an extent, referenced at .lamda. in FIG. 7, which may be selected
to extend over, for example, two or more pipe corrugations.
Together with the extents of the other tangs 74, theses extents
define a circumferential wall portion, referenced at 98 in FIG. 5,
of the collet 20 which, in turn, defines the major inner diametric
extent of the collet forward portion 70. Each of the tangs 74,
which may be formed of a metal such as brass, may be machined,
molded, cast, sintered such as by powdered metallurgy, or,
preferably, metal injection molded for more precise dimensional
tolerance, or otherwise formed.
[0044] The collar 76 forming the collet rearward portion 72 may be
molded, stamped, machined or otherwise formed of a plastic or,
alternatively, of another material such a metal, and is provided to
allow for the resilient expansion of the collet forward portion 70
such that the primary pipe 4 may received coaxially therethrough.
In that regard, the collar 76 may have an inner diametric extent
which generally matches the major inner diametric extent of the
collet forward portion 70 so as to provide a generally smooth
transition therebetween, and which further may be only
incrementally larger than the pipe major outer diameter to guide
and support the primary pipe 4 as the distal end 12 thereof is
being inserted into the fitting.
[0045] The collar 76 extends along an axial length, referenced at
"L" in FIG. 6, from a rearward end 100 to a forward end 102. Such
length, as with the tang length .lamda. (FIG. 6), may be selected
to extend over, for example, two or more pipe corrugations, and
defines a circumferential wall portion of the collar 76.
[0046] The collar rearward end 100 may be configured, as shown, as
being divided into a series of rearward segments, one of which is
referenced at 104, by a corresponding series of notches or other
rebates, one of which is referenced at 106. Each of the segments
104, which thereby afford the collar rearward end 100 a degree of
resiliency, i.e., to be expanded or collapsed, may have a distal
end 108 and a proximal end 110, and may be formed at the distal end
108 as a shoulder 112, having a forward surface 113, and a tapered,
rearward surface 114. As is shown, the shoulder 112 may extend
generally continuously about axis 26 intermediate between the
rebates 106, although it should be appreciated that the shoulder
112 instead may be interrupted or otherwise discontinuous about the
axis 26 between the rebates 106.
[0047] At the forward end 102, collar 76 may be "crenellated," or
otherwise notched, indented, or rebated, one of which is referenced
at 120, so as to again form a series of forward segments, one of
which is referenced at 122, which may correspond in number to the
number of tangs 74. Each of the segments 122 may have a generally
L-shaped cross-section, and as joined to a corresponding one of the
collet forward portion tangs 74, functions as a "living hinge" for
biasing the collet forward portion in its normally closed
orientation, while allowing for the resilient expansion or opening
of the collet forward portion 70 from such orientation to an
expanded or open orientation enlarging the minor inner diametric
extent such that the major outer diameter of the primary pipe 4 is
receivable therethrough. An upstanding portion 124 of each of the
forward segments 122 may be molded into, interference or snap fit,
bonded, or otherwise joined within a slot 82 of a corresponding one
of the tangs 74. As assembled, the forward surface 113 of the
collar rearward end 100 is axially spaced-apart as at 126 from the
backside surface 86 of the tang rearward ends 80.
[0048] Depending upon such factors as the stiffness of the material
of construction for the collar 76 and the degree of resiliency or
flexibility desired in the expansion of the collet forward portion
70, the depth of the rebates 120 and, accordingly, the effective
length, referenced at .lamda. in FIG. 4, of the segments 122, may
be adjust to achieve the desired response. By adjusting length of
the depth of the rebates 120 and the length of the collar segments
122, differing degrees of flexibility may be achieved for the
opening of the tangs 74 in the expansion of the collet forward
portion 70.
[0049] Returning to FIGS. 1 and 2, the fastener 8 in the
illustrated embodiment is configured generally as a hexagonal,
cap-type nut which may be formed of the same or different metal or
other material as the body 7. The fastener 8 is journaled coaxially
over the collar rearward end 100, and is seated on the collet 20,
such as in the space between a collar forward surface 113 and the
tang backside surfaces 86 for a removable, threaded engagement with
the fitting body rearward end portion 30. The fastener 8 thus
extends from an open forward end to a rearward end, which includes
a radially inwardly-projecting, primary shoulder portion 134 having
an opening 136, which is sized to retain the fastener 8 in the
space between the collet surfaces 113 and 86, while allowing for
primary pipe to be received concentrically through the opening 136
and the collet 20. The opening 136 may be sized to be incrementally
larger than the outer diameter of the collet collar 76 in the space
126 so as to provide support therefor as the pipe end is inserted,
and to assist in keeping the collet and pipe centered within the
connection.
[0050] The primary shoulder portion 134 defines a forwardly-facing,
generally annular end wall which, together with an adjoining
lateral wall 140, of an adjacent, internal secondary shoulder
portion, defines an internal pocket 144, which is sized to receive
the flanged rearward end 80 of the tangs 74. A forwardly-facing,
lead-in chamfer may be provided on the secondary shoulder portion
to help guide the tang ends 80 into the pocket 144 during the
make-up of the connection 10. During make-up, the seating of the
collet tangs 74 within the pocket 144 assists in keeping the collet
tangs closed and seated within the pipe corrugation.
[0051] The fastener 8 at its forward end portion 130 is internally
threaded at 152 for threadably engaging the external threads 34 on
the rearward end portion 30 of the fitting body. The inner diameter
of the threaded end portion of the fastener 8 is sized to provide a
clearance with the collet 20 to accommodate the radial outward
expansion of the collet tangs 74 as the pipe end 12 is inserted
therethrough.
[0052] Prior to the insertion of the primary pipe end and/or the
partial threading of the fastener 8 onto the fitting body for the
"pre-assembly" of the connection 10, the fastener 8 and collet 20
may be themselves be pre-assembled such as by inserting the collar
rearward end 100 through the fastener opening 136, with the
engagement of the collar rearward surface 114 with the opening 136
causing a camming action effecting the resilient collapse of the
diameter of the collar rearward end 100, such as may be
accommodated through the rebates 106 (FIG. 5), allowing the end 100
to be received through the fastener opening 136. Thereafter, the
fastener 8 may be partially threaded onto the body rearward end 30
with the collar rearward end 100 extending rearwardly externally of
the fastener 8, and with the fastener 8 being slidably movable
intermediate the collet surfaces 113 and 86.
[0053] Although optional, it may be preferred for ease of use and
to assure proper depth insertion of the primary tube, that a
positive spacing is provided controlling the distance that the
fastener 8 is partially threaded onto the body end 30. Such
spacing, as is shown in FIGS. 1 and 2, may be provided by a
tear-away plastic ring or other spacer 160, which may be interposed
between the forward end of the fastener and the radially enlarged
wrenching portion of the fitting body. The spacer may be torn-away
or otherwise removed prior to the torquing of the fastener 8. As is
shown, such spacer 160 may be sized to axially position the
fastener 8 relative to the body sealing surface 50 such that, upon
the insertion of the primary pipe and the seating of the tang
retaining portions 94 within the first pipe root 64, the axial
distance, referenced at "s" in FIG. 4, between the sealing surface
50 and the pipe distal end 12 is less than is necessary to further
advance the pipe past the second corrugation thereof before the
engagement of the pipe end 12 against the sealing surface 50.
Alternatively, the spacer 160 may be sized such that a positive
stop is established by the abutting engagement of the pipe end 12
against the sealing surface 50 upon the collet tangs retaining
portions 94 being received within the first pipe root 64. A
conventional thread locking material also may be substituted, such
material being coated onto the body threads 34 as applied either
from the forwardmost and extending rearwardly to a point defining
the forward position of the fastener 8 such that the fastener is
threaded, such as by hand, onto the uncoated threads with
additional torquing requiring a wrench or other tool. The locking
material alternatively may be applied to the threads beginning from
the rearwardmost and extending forwardly to a point define the
forward position of the fastener 8 such that the fastener is
threaded onto the coated portion of the threads and is "locked"
thereon with additional torquing again requiring a wrench to break
the lock. Visual inspection and/or tactile or audible, i.e., a
"snap," feedback also may be used to confirm the tube has been
inserted the proper amount into the fitting assembly.
[0054] In FIG. 2, the fitting assembly is shown pre-assembled for
receipt of the primary pipe. For the make-up of the connection, the
end of the primary pipe 4 may be inserted coaxially though the
collet collar rearward end 100 and the fastener opening 136
effecting the expansion or opening of the tangs 74 of the collet
forward portion 70 by the camming action developed by the bearing
of the tang surface 90 on the first pipe corrugation 60, with the
forward advancement of the collet being delimited by the abutting
engagement of the collar surface 113 against the fastener shoulder
134. Upon the forward advancement of the crest portion 62 of the
first corrugation 60 past the tang retaining portions 94, the tangs
74 resiliently return to their normal, unexpanded state with the
retaining portion 94 being receiving within the pipe root 64 as is
shown in FIG. 4. Thereupon, the make-up of the primary pipe to
fitting connection may be completed by the tearing-away or other
removal of the spacer 160, and the tightening of the fastener
8.
[0055] When the fastener 8 is tightened onto the fitting body, the
tang backside surfaces 86 will be advanced forwardly to the
position shown in FIG. 7 wherein the flanged rearward ends 80 of
the tangs 74 are received within the fastener internal pocket 144.
Further in such orientation, the fastener end wall 138 abuttably
engages the tang backside surface 86 in a force transmitting
communication urging the collet 20, along with the retained pipe
end 12, forwardly such that the collet tangs 74, as guided by the
tang chamfered surfaces 96 and the body lead-in chamfer 41, are led
coaxially along axis 26 into the socket of the body bore rearward
end portion 40. Therein, the opening of the collet tangs 74 is
constrained by the bore inner circumferential surface 42 which may
be sized to have an inner diameter which has a close tolerance with
the outer diameter of the collet wall portion 98. The body taper
43, moreover, may provide additional constraint against the opening
of the collet tangs 74 as the collet forward portion 70 is
continued to be advanced within the socket.
[0056] As the make-up of the connection continues, the pipe
corrugation 60 is collapsed and compressed between the collet tang
surfaces 92 and the body sealing surface 50 into the generally
flared configuration shown at 210, thereby effecting a fluid-tight,
preferably metal-to-metal, seal between such flare 210 and the body
surface 50 and the collet ring 95. As the make-up of the connection
proceeds from the insertion of the pipe end 12 to the forming of
the flare 210, it may be seen that the pipe outer diameter may be
closely supported over two or more, and, typically, four or five or
more corrugations, by the inner diameter of the collet 20. Such
support assists in guiding the pipe end 12 into the body socket 40,
and in ensuring that the pipe 4 is centered relative to the body
sealing surface 50, and may obviate the need and expense of forming
the fitting body 7 as having a separate sleeve or other structure
which must be received within the pipe inner diameter as a guide
for leading the pipe into the fitting.
[0057] In the illustrated embodiment, the diameter of the body apex
51 may be sized to be incrementally larger than the minor outer
diameter of the pipe 4 so as to provide a fold-over point
intermediate the major and minor outer diameters of the pipe 12
which initiates the inversion of the pipe corrugation 60 into the
flare 210. Moreover, as pipe 4 typically is cut to length with a
conventional C-clamp type pipe cutter or the like, the cut end 66
of the pipe could potentially scratch or otherwise damage the
surface 50. As such damage could affect the fluid-tight seal
between the surface 50 and the flare 210, a more reliable seal may
be provided by virtue of the described folding over of the flare.
Although it has been described that only the first pipe corrugation
is compressed, it will be appreciated that any number of
corrugations left projecting beyond the collet may be so compressed
and collapsed if the fitting componentry is sized accordingly. To
disconnect the primary pipe 4 from the fitting body 7, the
connection sequence simply is reversed.
[0058] Thus, the above-described fitting connection for the
corrugated primary pipe provides for easy and simple assembly, and
may be used to achieve a fluid-tight or other secure connection in
a single operation.
[0059] Secondary Pipe-Fitting Connection
[0060] In accordance with a preferred embodiment of the present
invention and as illustrated in FIGS. 2 and 3, the fastener 8 has a
tubular coupling portion 170 opposite its internally threaded
portion 130. The tubular coupling portion 170 is configured to
receive an end portion of the outer secondary (containment) pipe 5.
The coupling device 10 is provided to secure the end portion of the
outer containment pipe in fluid tight relationship to the tubular
coupling portion 170 of the fastener. The coupling device may
include one or more of a compression fitting, bonded joint, a
push-to-connect mechanism, or a clamp.
[0061] In the illustrated embodiment, the tubular coupling portion
170 is configured to have the end portion of the outer secondary
pipe 5 pushed thereover in a telescopic manner and then fastened in
a sealed relationship by a clamp 10. As shown, the outer surface of
the tubular coupling portion is formed with axially spaced apart,
annular ribs 174 that may have rounded radially outer ends as shown
to facilitate engagement with the inner diameter surface of the
corrugated secondary pipe. An annular seal 176 is provided to seal
the inner diameter of secondary pipe to the outer surface of the
tubular portion 170.
[0062] The clamp 10 may be of any suitable type. In the illustrated
embodiment, a T-bolt band clamp is used, the band thereof being
cinched around the secondary pipe. In the several figures, the
clamp is shown prior to tightening. When tightened, the clamp will
crush the underlying corrugations against the tubular coupling
portion and the seal 176 that provides a fluid-tight connection.
Other usable clamps are clamshell type clamps and worm gear clamps,
for example.
[0063] Fastener Access Port
[0064] As seen in FIGS. 2 and 3, the fastener 8 when tightened will
define with the fitting body and outer surface of the primary pipe
4, an interior space 180 that is in fluid communication with the
interstitial space 6 between the primary and secondary pipes. The
fastener also has an access port 182 extending from the interior
space 180 to the exterior of the fastener. The access port is
provided to enable external monitoring of the interstitial space
between the primary and secondary pipes.
[0065] The access port 182 may be in the form of a view port
allowing visual viewing of the interior space from outside the
fastener. This may be implemented by providing a sight glass in the
view port, such as a transparent or translucent lens in the wall of
the fastener for optical enhancement of an interior portion of the
interior space. The lens may have outer and inner surfaces, at
least one of which is curved to optically magnify the interior
space of the cavity. The lens may be secured in an opening in the
wall of the fastener or formed during molding of the fastener if
the fastener is formed from molded plastic.
[0066] The access port 182 may also provide for through access of a
sensor for detecting the presences and/or absence of fluid in the
interior space, or it may function as a test port providing for
connection of a conduit connected to a remotely located sensor. To
facilitate connection of a conduit thereto, such as a hose, tube,
etc., the port may be threaded. Preferably the portion of the
fastener forming the port does not project radially beyond the
wrenching surfaces 32 (FIG. 1) provided on the fastener so as not
to interfere with tightening (or loosening) of the fastener on the
fitting body.
[0067] To prevent leakage between the fastener 8 and fitting body
7, a seal 188 is provided. The seal, for example an O-ring, may be
carried in an annular groove on the outer diameter surface of the
fitting body such that it will be engaged and compressed when the
fastener is tightened onto the fitting body. In the illustrated
embodiment, the O-ring will seal against a cylindrical interior
surface located forwardly of the internal threads of the fastener.
The cylindrical surface may transition to a leading beveled surface
at the leading end of the fastener.
[0068] To provide for increased flow area between the primary and
secondary pipes and more particularly between the interstitial
space 6 and the interior space 180 at the regions of the radially
outwardly disposed annular crests, the crests 62 of the corrugated
primary pipe 4 can be dented to form one or more axially extending
recesses 192 as illustrated in FIG. 8. Preferably, each crest had
formed therein a plurality of the recesses that are annularly
spaced apart.
[0069] As it is anticipated that certain changes may be made in the
present invention without departing from the precepts herein
involved, it is intended that all matter contained in the foregoing
description shall be interpreted in as illustrative rather than in
a limiting sense. All references including any priority documents
cited herein are expressly incorporated by reference.
[0070] Although the invention has been shown and described with
respect to a certain embodiment or embodiments, it is obvious that
equivalent alterations and modifications will occur to others
skilled in the art upon the reading and understanding of this
specification and the annexed drawings. In particular regard to the
various functions performed by the above described elements
(components, assemblies, devices, compositions, etc.), the terms
(including a reference to a "means") used to describe such elements
are intended to correspond, unless otherwise indicated, to any
element which performs the specified function of the described
element (i.e., that is functionally equivalent), even though not
structurally equivalent to the disclosed structure which performs
the function in the herein illustrated exemplary embodiment or
embodiments of the invention. In addition, while a particular
feature of the invention may have been described above with respect
to only one or more of several illustrated embodiments, such
feature may be combined with one or more other features of the
other embodiments, as may be desired and advantageous for any given
or particular application.
* * * * *